This invention generally relates to vent assemblies and methods of making same, and, particularly, to barrier vent assemblies which are constructed to prevent or hinder passage of rigid articles through the vent openings.
Vent assemblies are often required to provide air ventilation to electrical equipment or the like contained within equipment enclosures. For safety reasons, such vent assemblies are often guarded to prevent direct access through the vent openings to a live electrical part or moving mechanical part of the equipment contained within the inclosure. In particular, the Underwriters Laboratory standard for panelboard ventilating openings provides that "A ventilation opening--slot, louver, or the like--shall be protected by one or more baffles, barriers, or other obstructions of such dimensions and locations that any access path to a live part requires at least two deviations of direction from a straight line." (see UL Standard 67, Section 5.14).
Known designs for meeting this standard have included baffled vent openings with barrier plates or the like mounted in a location spaced from and behind the baffles to block direct or straight line access. Other designs employ a wire mesh in lieu of the barrier plate. Designs are also known which employ a pair of members mounted adjacent the vent opening in cooperative blocking relationship.
These designs achieve the desired objective of access. Unfortunately, the many parts and their arrangement requires the making of numerous weld joints during assembly which adds to the costs of labor and materials in constructing the vent assemblies. In addition, some of these designs result in an undesirably thick, or high profile, vent assembly.